寬中頻頻寬金氧半混波器設計

Abstract

本篇論文主要描述寬中頻的降頻混波器，並為了，RF選在8.7GHz - 17.4GHz，LO固定在17.4GHz，IF則接近DC-8.7GHz。本設計以0.18um CMOS製程，為了不造成系統相當程度的衰落降級，會特別注意對於一些應用在類比電路，或者是應用在幾GHz範圍的設計細節。為了增加訊號轉換的效益，並且為了減少在RF端的電路的共模訊號，以及不要的差模諧波訊號，在RF端電路採用被動式的Marchand巴倫。為了降低電路的偏壓，將轉導對的電流，旁路不經過四個混波的電晶體，並且用IF巴倫將輸出的差動訊號轉換成單端訊號。 相關的電路理論將被發掘，並期望能夠用模擬和量測結果來確認。操作的更高頻RF的類似的混波器，也在計畫實現當中，以利精密的寬中頻接收模組的研發。

This papers describes the development of a wide-IF-bandwidth down converting mixer, with the RF frequency chosen to be 8.7–17.4GHz, LO fixed at 17.4 GHz and IF close to DC–8.7GHz. The design of this 0.18um CMOS mixer demands particular attention to details, as some techniques developed in the analog and even a few GHz frequency range cannot be directly applied without causing considerable system degradations. To increase the signal transfer efficiency and minimize all the common-mode signals and those unwanted differential mode harmonics at RF circuit, a passive Marchand balun is adopted in designing this mixer's RF circuit. To minimize the circuit's bias voltage Vbias, the drain current of the transconductor pair is set to completely by-pass the four mixing transistors, and IF active balun is applied to convert the output differential signal to single-ended signal. Related circuit theories will be explored and expect to be confirmed by using both simulated and measured results. Similar mixers that operates at much higher RF frequencies have also been planned, thus facilitate the development of a compact wide-IF-bandwidth receiver module.